The purpose of this collaborative study is to provide a definitive and conclusive diagnosis of depression of adolescent children who reported high levels of depressive symptoms in a lay-administered questionnaire during the first-stage sampling of children in a local school system. In addition, a representative sample of children was also assessed as a control. These children, who were between 12 and 14 years old, have participated in a longitudinal study since entering first grade. Each year they have been assessed on a variety of dimensions including mental health, school achievement, drug use, and family life. In addition, during the first two years of school, an intervention aimed at decreasing depression and drug use in adolescence was given. After the first-stage sampling, children who agreed to participate came to the Prevention Research Center for a 2 to 3 hr interview along with a parent. At that time, they were administered the K-SADS plus some additional diagnostic instruments including the CIDI. The mother was interviewed as well as part of the K-SADS assessment. The interviews were videotaped and the tapes will eventually be used by a group of clinicians to make a consensus diagnosis. A total of 202 letters were mailed. Of these, 136 were selected because the student had scoring positively for depression during the spring assessment. An additional 66 students were randomly selected as controls. Of these 202 families, we were able to contact 167 families by phone, and, of those, 116 were interviewed (70%). Currently, extensive analyses of the data are being conducted. These analyses will include: 1) a quantitative assessment of the test-retest reliability of the CIDI, and 2) a comparison of both CIDI's and the K-SADS. In order to establish a definitive DSM-IIIR diagnosis, a team of clinicians is being formed to co-evaluate the videotaped K-SADS interviews. It is likely that a host of additional analyses will be conducted, even using data from future assessments in this ongoing longitudinal study.